With 4, "Power Drain" may be added to a Weapon of your own design through Create Artifact, though there is clearly no reason to do so.

It also appears on 9 of the 250 pre-defined Magical Items in Treasure. The Spellbook requirements for finding these items are irregular, and "Power Drain" weapons rarely appear due to these restrictions. Despite this property's dead weight, some of these prefab weapons have very useful stats and powers and are worth keeping. Whether crafted or found, "Power Drain" itself is only useful for smashing on the anvil for a profit in Mana Crystals.